text: A wide range of techniques is available to evaluate chemotactic activity of cells or the chemoattractant and chemorepellent character of ligands.
  The basic requirements of the measurement are as follows:
  * Concentration gradients can develop relatively quickly and persist for a long time in the system
  * Chemotactic and chemokinetic activities are distinguished
  * Migration of cells is free toward and away on the axis of the concentration gradient
  * Detected responses are the results of active migration of cells
  Despite the fact that an ideal chemotaxis assay is still not available, there are several protocols and pieces of equipment that offer good correspondence with the conditions described above. The most commonly used are summarised in the table below: